Lately I have been checking out the sky. What catches my attention most are clouds. Not only are they amazingly beautiful, they are also amazingly difficult to paint - no matter what color they are.
Here's an illustration of what I mean:
This photograph is from June of 2015. D and I were in D.C. and had gone to a Nationals' baseball game. If I remember correctly, the game hadn't even started when a severe thunderstorm started rolling in from Ohio (I think). With the storm, as usual, came clouds, but these were made remarkable because of the color.
So if the question of clouds is accepted as within the normal range of difficulties painters face, then imagine this. If you were looking at a realistic painting that included clouds this color, what would you think?